Mind Map, is a fine for assoziation and connections of ideas around one theme.

Disney Method is a method, where you wear different hats and suround a problem by four phases of mood: first outsider, then dreamer, realiser and last is critics. Its quite close to Six Thinking Hats, where you literally wear six hats.

Tag Clouds, is a good tool for bundle tags or claims of stakeholders into a shared vision.

In case you take this Tag Clouds as a starting point, semantic fields open wide with help of synonyms, metaphors, association and etymology.

Sketching and drawing, for showing your "unsharp" idea.

Describe your idea in one or two sentences and become more clear..

Storyboard is good for visualise a behaviour or temporal scences. It gives a good feeling for your goal.

Method acting would give you more feeling of your user, but Im not sure if it makes sense for UX. It would be placed more in the beginning like moodboard or tag cloud is.

We use sketching a lot ... either (1) the whole team working in parallel on designs, followed by a review workshop with the client (the workshop is the 'deliverable', not the sketches themselves), or (2) even collaborative sketching that also includes the clients (based on the premise that 'anyone can sketch' and we are generating IDEAS not works of art) - the latter can be particularly helpful if working with teams of devs who have to implement the ideas later - helps them get a better appreciation and 'buy-in' to the solutions.

Something that gets the designer away from the computer screen and bashing out ideas in a more practical, hands on, even seemingly abstract way.

Get in a room with the team with a white board. Bring coffee and donuts.

In the various places I've worked, I've always found that setting to be the most enjoyable and productive UX work--especially when you can bring in other stakeholders as well...business line managers...project managers...analysts...dev team rep's, etc.